Comparison Analysis for Cross‐Regulation in Hybrid Conduction Mode SIDO Buck Converter With Constant/Dynamic‐Freewheeling Control

ABSTRACT Hybrid conduction mode (HCM) control with a single freewheel phase is applied to reduce switching loss and minimize cross‐regulation in single‐inductor dual‐output (SIDO) dc–dc converter. However, the cross‐regulation still exists when the load‐step occurs, especially when the freewheel current is instantaneously adjusted based on load conditions. To explore the deep effect of the freewheel current in constant freewheel (CF)/dynamic freewheel (DF) control, the comparison analysis of cross‐regulation is presented in this paper. The small‐signal models of the HCM SIDO buck converter with CF/DF control are established, and the characteristics of closed‐loop cross‐regulation and load transient under different load current coefficients for freewheel current are discussed. The simulation results and the experimental results show that compared with the CF control, the transient performance of the output branch is significantly improved at different gain coefficients when the DF control is adopted. When k a = 1 and k b = 0, the cross‐regulation of the CCM branch on the PCCM branch can decrease from 19.17% to 4.17%, while retaining the zero cross‐regulation of the PCCM branch on the CCM branch.